During the twentieth century otter (Lutra lutra) populations in central and western Europe declined and became fragmented because of habitat alterations, chemical pollution and direct persecution. In this study we used microsatellites to describe spatial patterns of genetic diversity and subdivision in otters from eight populations in Europe. Genetic diversity was moderately high within populations (He = 0.45-0.77), and significantly partitioned among locations (FST = 0.17; RST = 0.16; P < 0.001). A Bayesian cluster analysis of multilocus genotypes assigned individuals to seven genetically distinct groups, which were partly concordant with the geographical origin of the samples. An assignment test of the individuals to the populations showed that the Danish and, to a lesser extent, the Spanish populations were unique and distinct, whereas the other populations were partially admixed. Inference of past demographic fluctuations from coalescent analysis suggested that otter populations probably declined several thousand years ago, with the exception of the Irish population for which no such decline could be detected. No genetic evidence for recent bottlenecks was found. The historical decline could stem from post-glacial founding events and recolonization of northern Europe after the last glacial maximum, or from more recent dry stages in the early Holocene in central Europe. On the basis of these results, we recommend that recovery plans should promote the expansion of existing natural populations through improvements of river and wetland habitats.

Successful management of endangered species may be greatly facilitated by the ability to monitor population trends. The Australian northern hairy-nosed wombat (Lasiorhinus krefftii) is one of the world's most endangered mammals, but precise abundance estimation by trapping surveys has proven exceedingly difficult. A mark-recapture study was conducted in the sole remaining L. krefftii population, based on microsatellite identification of individuals and their gender from DNA in remotely collected single hairs. Population size was estimated to be 113 (95% confidence interval of 96 to 150). This suggests an increase in population size over the previous estimate of 65 (95% CI 42-186) in 1993, although the estimates did not differ significantly. There was a significant male bias in the sex ratio (2.25 males:1 female), in agreement with recent trapping surveys. The non-invasive approach used here is vital for estimating population size and trends, and hence it is the most important recent advance in the conservation management of the northern hairy-nosed wombat.

Rare bouts of extreme environmental perturbations (catastrophes) have been predicted to have a major influence on the probability of extinction. Yet very little information is available on the frequency and severity of catastrophes. Improving the available information concerning catastrophe parameters would allow for an evaluation of their effect and a start towards understanding their causes. We used the Global Population Dynamics Database to determine the frequency and severity of die-offs in 88 species of vertebrates. We define a catastrophe as any 1-year decrease in population size of 50% or greater. The data yielded three findings. (1) The frequency of severe die-offs in vertebrate populations is strongly related to the generation length of the organism. (2) The probability of a severe die-off for a particular population is approximately 14% per generation. (3) The frequency of die-off severity can be modelled as a modified power function with the frequency of die-offs decreasing with increasing magnitude of effect. The distribution is not consistent with catastrophes stemming from environmental sources different than those responsible for smaller fluctuations, but seems to represent the tail of a continuous distribution of environmental perturbations.

We show a direct impact of El Niño/Southern Oscillation (ENSO) related fires on the demography and persistence of the siamang (Symphalangus syndactylus), a frugivorous, Southeast Asian rainforest primate. Siamang groups affected by ENSO-related wildfires in a Sumatran rainforest were significantly smaller and experienced significantly lower infant and juvenile survival. Likelihood of infants surviving to subadults was higher by a factor of 2.8 for groups in undisturbed habitat. Burn groups had access to 48% fewer reproductive-size strangling fig trees in their territories, compared to non-burn groups. Dietary and foraging behaviour changes associated with habitat disturbance may result in lower productivity and higher mortality of young animals. Reproductive potential of burn groups is insufficient to offset low survival and groups are unlikely to persist for more than two generations. Increasing frequency of ENSO events increases the likelihood that siamang and other long-lived species that rely on fruiting trees will experience multiple fires within one generation; the resulting reduction in seed dispersal services will slow recovery of burned forest.

This paper applies the ‘choice experiment’ method to investigate public preferences over the design of wild goose conservation policy in Scotland. We argue that this method can shed useful light on the design of conservation policy, allowing policy-makers to take account of people's preferences, be they members of the general public (whose taxes often pay for conservation actions), local residents more directly affected by the policy, or visitors to wildlife areas. Preferences can be quantified in economic terms, so that the costs and benefits of different policy designs can be compared. In our study, we find that the general public, local residents and visitors have very different preferences for the conservation of geese. Whether geese are shot, the endangered status of geese, the spatial targeting of conservation and the size of the goose population all have impacts on the perceived benefits of conservation. In general, though, people are willing to pay for wild geese conservation.

We examine the abundance and distribution of Sumatran tigers (Panthera tigris sumatrae) and nine prey species in Bukit Barisan Selatan National Park on Sumatra, Indonesia. Our study is the first to demonstrate that the relative abundance of tigers and their prey, as measured by camera traps, is directly related to independently derived estimates of densities for these species. The tiger population in the park is estimated at 40-43 individuals. Results indicate that illegal hunting of prey and tigers, measured as a function of human density within 10 km of the park, is primarily responsible for observed patterns of abundance, and that habitat loss is an increasingly serious problem. Abundance of tigers, two mouse deer (Tragulus spp.), pigs (Sus scrofa) and Sambar deer (Cervus unicolor) was more than four times higher in areas with low human population density, while densities of red muntjac (Muntiacus muntjac) and pigtail macaques (Macaca nemestrina) were twice as high. Malay tapir (Tapirus indicus) and argus pheasant (Argusianus argus), species infrequently hunted, had higher indices of relative abundance in areas with high human density. Edge effects associated with park boundaries were not a significant factor in abundance of tigers or prey once human density was considered. Tigers in Bukit Barisan Selatan National Park, and probably other protected areas throughout Sumatra, are in imminent danger of extinction unless trends in hunting and deforestation are reversed.

Conservation practices are supposed to get refined by advancing scientific knowledge. We study this phenomenon in the context of monitoring tiger populations in India, by evaluating the ‘pugmark census method’ employed by wildlife managers for three decades. We use an analytical framework of modern animal population sampling to test the efficacy of the pugmark censuses using scientific data on tigers and our field observations. We identify three critical goals for monitoring tiger populations, in order of increasing sophistication: (1) distribution mapping, (2) tracking relative abundance, (3) estimation of absolute abundance. We demonstrate that the present census-based paradigm does not work because it ignores the first two simpler goals, and targets, but fails to achieve, the most difficult third goal. We point out the utility and ready availability of alternative monitoring paradigms that deal with the central problems of spatial sampling and observability. We propose an alternative sampling-based approach that can be tailored to meet practical needs of tiger monitoring at different levels of refinement.

Studies on the effects of nonindigenous invasive species and habitat fragmentation on native ecosystems have become priorities for conservation biologists. This is relevant particularly for islands with high degrees of endemism. In the present paper the role of fragmentation and possible effects of introduced Rattus rattus on endemic rodents (Macrotarsomys bastardi and Eliurus spp.) and the gray mouse lemur (Microcebus murinus) were assessed for dry deciduous forests in Madagascar. Capture rates of endemic rodents declined significantly with declining fragment size. Macrotarsomys bastardi was never caught in primary forest fragments < 600 ha or outside the primary forest but captures of M. bastardi were correlated to changes in vegetation structure associated with fragmentation rather than to fragment size per se. Eliurus spp. were also found in small primary-forest fragments and in secondary forests close to primary forests, suggesting that secondary forests can serve as buffer zones or corridors for this species. The lemur M. murinus was caught in all types of primary and secondary forest. This species did not seem to respond to fragmentation of primary forests. Even though it was found in most secondary-forests, capture rates declined as these secondary forest formations increased in size. This indicates that secondary forests are suboptimal habitats for M. murinus. Rattus rattus were caught in all vegetation formations except for the open savanna. Their capture rates increased as forest fragments became smaller, indicating that mosaics of different habitat types are beneficial for introduced rats. There was no significant relation between capture rates of R. rattus and the endemic species. In conclusion, these results suggest that (1) native Malagasy rodents of the dry deciduous forest are more sensitive towards forest disturbance than M. murinus; (2) there is no indication for negative interactions between introduced rats and the native small-mammal fauna.

To achieve long-term viability of hunted puma (Puma concolor) populations (even at historically low densities), we propose a management plan based on the metapopulation concept that designates source areas (closed to hunting) and sink areas (open to hunting). We use 11 years of data from Idaho and Utah to demonstrate how the proposed management plan might be implemented. We use minimum and maximum densities of resident animals to calculate minimum and maximum effective population sizes, neighbourhood areas (regional management units) and usable habitat within the units. We designate sink and source areas based on their size, accessibility to hunters and juxtaposition. We show that closing 63% of puma habitat to hunting would ensure long-term puma population viability while permitting traditional hunting levels in other areas. This system could be adapted to existing state (and interstate) hunting management units, and we outline several steps by which wildlife agencies might set up a process (including public participation) to manage puma hunting.

Umbrella species are ‘species with large area requirements, which if given sufficient protected habitat area, will bring many other species under protection’. Historically, umbrella species were employed to delineate specific reserve boundaries but are now used in two senses: (1) as aids to identifying areas of species richness at a large geographic scale; (2) as a means of encompassing populations of co-occuring species at a local scale. In the second sense, there is a dilemma as to whether to maximize the number or viability of background populations; the umbrella population itself needs to be viable as well. Determining population viability is sufficiently onerous that it could damage the use of umbrella species as a conservation shortcut. The effectiveness of using the umbrella-species concept at a local scale was investigated in the real world by examining reserves in East Africa that were gazetted some 50 years ago using large mammals as umbrella species. Populations of these species are still numerous in most protected areas although a few have declined. Populations of other, background species have in general been well protected inside reserves; for those populations that have declined, the causes are unlikely to have been averted if reserves had been set up using other conservation tools. Outside one reserve, Katavi National Park in Tanzania, background populations of edible ungulates and small carnivores are lower than inside the reserve but small rodent and insectivore abundance is higher. While we cannot compare East African reserves to others not gazetted using umbrella species, the historical record in this region suggests that umbrella species have been an effective conservation shortcut perhaps because most reserves were initially large and could encompass substantial populations of background species. It is therefore premature to discard the local-scale umbrella-species concept despite its conceptual difficulties.

Using published IUCN red-lists for the threatened bird species of Indonesia (Stattersfield & Capper, 2000), we document that the species at risk in Indonesia are not a taxonomically random sample, consistent with patterns seen at the global scale (Purvis et al., 2000). This implies that a greater than random proportion of Indonesia's and the world's (through the loss of endemics) phylogenetic diversity (PD) is at risk (Von Euler, 2001). Using cytochrome b (Johns & Avise, 1998) and a distance-based taxonomy, we attempt to quantify this projected loss of PD in millions of years and conclude with a brief discussion of the conservation implications for Indonesia, and of the use of ‘evolutionary heritage’ as a measure for conservation at the geopolitical level.